Encoding and decoding methods for secure scalable streaming and related systems

ABSTRACT

A method and system for securely and scalably encoding data are disclosed. A method and system for decoding data which has been securely and scalably encoding are also disclosed. In one encoding method embodiment, the present invention recites receiving data. The present method then segments the data into corresponding regions. The regions are then scalably encoded into scalable data. The present embodiment then progressively encrypts the scalable data to generate progressively encrypted scalable data. Next, the present embodiment packetizes the progressively encrypted scalable data.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of the co-pending,commonly-owned U.S. Patent Application with Ser. No. 09/849,794 andAttorney Docket No. 10014738-1, filed May 4, 2001, by S. Wee et al., andentitled “Encoding and Decoding Methods for Secure Scalable Streamingand Related Systems.”

TECHNICAL FIELD

The present claimed invention relates to the field of streaming media.More specifically, the present claimed invention relates to the encodingand decoding of data.

BACKGROUND ART

Wireless streaming environments present many challenges for the systemdesigner. For instance, clients can have different display, power,communication, and computational capabilities. In addition, wirelesscommunication links can have different maximum bandwidths, qualitylevels, and time-varying characteristics. A successful wireless videostreaming system must be able to stream video to heterogeneous clientsover time-varying wireless communication links, and this streaming mustbe performed in a scalable and secure manner. Scalability is needed toenable streaming to a multitude of clients with different devicecapabilities. Security is particularly important in wireless networks toprotect content from eavesdroppers.

In order to achieve scalability and efficiency in wireless streamingenvironments, one must be able to easily adapt or transcode thecompressed video stream at intermediate network nodes. A transcodertakes a compressed video system as the input, then processes it toproduce another compressed video stream as the output. Sampletranscoding operations include bitrate reduction, rate shaping, spatialdownsampling, frame rate reduction, and changing compression formats.Network transcoding can improve system scalability and efficiency, forexample, by adapting the spatial resolution of a video stream for aparticular client's display capabilities or by dynamically adjusting thebitrate of a video stream to match a wireless channel's time-varyingcharacteristics.

While network transcoding facilitates scalability in video streamingsystems, it also presents a number of challenges. First, whilecomputationally efficient transcoding algorithms have been developed,even these are not well-suited for processing hundreds or thousands ofstreams at intermediate wired network nodes or even a few streams atintermediate low-power wireless networking relay nodes. Furthermore,network transcoding poses a serious threat to the security of thestreaming system because conventional transcoding operations performedon encrypted streams generally require decrypting the stream,transcoding the decrypted stream, and then re-encrypting the result.Because every transcoder must decrypt the stream, each networktranscoding node presents a possible breach in the security of theentire system.

More specifically, in conventional video streaming approaches employingapplication-level encryption, video is first encoded into a bitstreamusing interframe compression algorithms. These algorithms include, forexample, the Moving Picture Experts Group (MPEG) standard, theInternational Telecommunications Union (ITU) standard, H.263, orintraframe compression algorithms such as, for example, the JointPhotographic Experts Group (JPEG) or JPEG2000 standards. The resultingbitstream is then encrypted, and the resulting encrypted stream ispacketized and transmitted over the network using a transport protocolsuch as unreliable datagram protocol (UDP). Prior Art FIG. 1 is a blockdiagram 100 which illustrates the order in which conventionalapplication-level encryption is performed (i.e. Encode 102, Encrypt 104and Packetize 106). One difficulty with this conventional approacharises when a packet is lost. Specifically, error recovery is difficultbecause without the data from the lost packet, decryption and/ordecoding may be difficult if not impossible.

Prior Art FIG. 2 is a block diagram 200 illustrating anotherconventional secure video streaming system that uses network-levelencryption (i.e. Encode 202, Packetize 204, and Encrypt 206). The systemof Prior Art FIG. 2 can use the same video compression algorithms as thesystem of Prior Art FIG. 1. However, in the system of Prior Art FIG. 2,the packetization can be performed in a manner that considers thecontent of the coded video and thus results in better error recovery, aconcept known to the networking community as application-level framing.For example, a common approach is to use MPEG compression with the RTPtransport protocol which is built on unreliable datagram protocol (UDP),RTP provides streaming parameters such as time stamps and suggestsmethods for packetizing MPEG payload data to ease error recovery in thecase of lost or delayed packets. However, error recovery is stilldifficult and without data from a lost packet, decryption and/ordecoding is still difficult if not impossible.

Both of the conventional approaches of Prior Art FIG. 1 and Prior ArtFIG. 2 are secure in that they transport the video data in encryptedform. However, with these conventional approaches, if networktranscoding is needed, it must be performed in accordance with themethod of Prior Art FIG. 3. That is, as shown in block diagram 300, thenecessary transcoding operation is a decrypt 302, decode 304, process306, re-encode 308, and re-encrypt 310 process. As shown in the blockdiagram 400 of Prior Art FIG. 4, in another conventional approach, thecomputational requirements of the operation of Prior Art FIG. 3 arereduced to a decrypt 402, transcode 404, and re-encrypt 406 process.Specifically, this computational reduction is achieved by incorporatingand efficient transcoding algorithm (i.e. transcode module 404) in placeof the decode 304, process 306, and re-encode 308 modules of Prior ArtFIG. 3. However, even such improved conventional transcoding algorithmshave computational requirements that are not well-suited for transcodingmany streams in a network node. Furthermore, a more critical drawbackstems from the basic need to decrypt the stream for every transcodingoperation. As, mentioned above, each time the stream is decrypted, itopens another possible attack point and thus increases the vulnerabilityof the system. Thus, each transcoder further threatens the security ofthe overall system.

As yet another concern, wireless streaming systems are limited bywireless bandwidth and client resources. Wireless bandwidth is scarcebecause of its shared nature and the fundamental limitations of wirelessspectrum. Client resources are often practically limited by powerconstraints and by display, communication, and computationalcapabilities. As an example, wireless transmission and even wirelessreception alone typically consume large power budgets. In order to makethe most efficient use of wireless bandwidth and client resources, it isdesirable to send clients the lowest bandwidth video streams that matchtheir display and communication capabilities. In wireless streamingsystems where a sender streams video to a number of heterogeneousclients with different resources, network transcoders can be used tohelp achieve end-to-end system efficiency and scalability.

In hybrid wired/wireless networks, it is often necessary tosimultaneously stream video to fixed clients on a wired network and tomobile clients on a wireless network. In such a hybrid system, it mayoften be desirable to send a full-bandwidth, high-resolution videostream to the fixed wired client, and a lower-bandwidth,medium-resolution video stream to the mobile wireless receiver.Conventional video streaming approaches, however do not achieve theefficiency, security, and scalability necessary to readily accommodatethe video streaming corresponding to hybrid wired/wireless networks.

Yet another example of the drawbacks associated with conventional videostreaming approaches is demonstrated in conjunction with wirelessappliance networks. In many wireless appliance networks, mobile sendersand receivers communicate with one another over wireless links. Asender's coverage area is limited by the power of the transmittedsignal. Relay devices can be used to extend the wireless coverage areawhen intended receivers are beyond the immediate coverage area of thesender. However, in the case of heterogeneous clients within the samewireless network, it may be desired to provide a higher bandwidth,high-resolution video stream to the high power wireless receivers, and alower bandwidth, low-resolution video stream to the low power wirelessreceivers. Once again, conventional video streaming approaches, howeverdo not achieve the efficiency, security, and scalability necessary toreadily accommodate such video streaming demands in wireless appliancenetworks. Although the above-listed discussion specifically mentions theshortcomings of prior art approaches with respect to the streaming ofvideo data, such shortcomings are not limited solely to the streaming ofvideo data. Instead, the problems of the prior art span various types ofmedia including, but not limited to, audio-based data, image-based data,graphic data, web page-based data, and the like.

Thus, the need has arisen for a secure and scalable encoding method andsystem for use in the streaming of data. A further need exists for amethod and system for decoding data which has been securely and scalablyencoded.

DISCLOSURE OF THE INVENTION

The present invention provides, in one embodiment, a secure and scalableencoding method and system for use in the streaming of data. The presentinvention further provides, in one embodiment, a method for decodingdata which has been securely and scalably encoded.

Specifically, in one embodiment, the present invention recites receivingdata. The present method then segments the data into correspondingregions. The regions are then scalably encoded into scalable data. Thepresent embodiment then progressively encrypts the scalable data togenerate progressively encrypted scalable data. Next, the presentembodiment, packetizes the progressively encrypted scalable data.

In another embodiment, the present invention recites a method fordecoding data which has been securely and scalably encoded. In thisembodiment, the present invention receives a packet containingprogressively encrypted and scalably encoded data. The presentembodiment decrypts the packet containing the progressively encryptedand scalably encoded data to generate scalably encoded regions. Thepresent invention then decodes the scalably encoded regions to providedecoded regions. Next, the present embodiment assembles the decodedregions to provide data.

These and other technical advantages of the present invention will nodoubt become obvious to those of ordinary skill in the art after havingread the following detailed description of the preferred embodimentswhich are illustrated in the various drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention:

PRIOR ART FIG. 1 a block diagram which illustrates the order in whichconventional application-level encryption is performed.

PRIOR ART FIG. 2 is a block diagram which illustrates anotherconventional secure streaming system using network-level encryption.

PRIOR ART FIG. 3 is block diagram illustrating a conventionaltranscoding method.

PRIOR ART FIG. 4 is block diagram illustrating another conventionaltranscoding method.

FIG. 5 is a schematic diagram of an exemplary computer system used toperform steps of the present method in accordance with variousembodiments of the present claimed invention.

FIG. 6 is a flow chart of steps performed in a secure and scalableencoding method in accordance with one embodiment of the present claimedinvention.

FIG. 7 is a block diagram of an encoding system in accordance with oneembodiment of the present claimed invention.

FIG. 8 is a block diagram of an encoding system having a videoprediction unit (VPU) coupled thereto in accordance with one embodimentof the present claimed invention.

FIG. 9 is a block diagram of an encoding system having a videoprediction unit (VPU) integral therewith in accordance with oneembodiment of the present claimed invention.

FIG. 10A is a schematic depiction of a frame of video data in accordancewith one embodiment of the present claimed invention.

FIG. 10B is a schematic depiction of the frame of video data of FIG. 10Aafter segmentation into corresponding regions in accordance with oneembodiment of the present claimed invention.

FIG. 10C is a schematic depiction of the frame of video data of FIG. 10Aafter segmentation into corresponding non-rectangular regions inaccordance with one embodiment of the present claimed invention.

FIG. 10D is a schematic depiction of the frame of video data of FIG. 10Aafter segmentation into corresponding overlapping non-rectangularregions in accordance with one embodiment of the present claimedinvention.

FIG. 11 is a flow chart of steps performed in decoding data which hasbeen securely and scalably encoded in accordance with one embodiment ofthe present claimed invention.

FIG. 12 is a block diagram of a decoding system in accordance with oneembodiment of the present claimed invention.

FIG. 13 is a block diagram of a decoding system having a videoprediction unit (VPU) coupled thereto in accordance with one embodimentof the present claimed invention.

FIG. 14 is a block diagram of a decoding system having a videoprediction unit (VPU) integral therewith in accordance with oneembodiment of the present claimed invention.

FIG. 15A is a block diagram of an exemplary hybrid wired/wirelessnetwork upon which embodiments of the present invention may bepracticed.

FIG. 15B is a block diagram of an exemplary wireless network upon whichembodiments of the present invention may be practiced.

FIG. 16 is a block diagram of a source node, an intermediate(transcoder) node, and a receiving node in accordance with oneembodiment of the present invention.

FIG. 17 is a block diagram of one embodiment of a transcoder device uponwhich embodiments of the present invention may be practiced inaccordance with one embodiment of the present claimed invention.

FIGS. 18A, 18B, 18C, 18D and 18E are data flow diagrams illustratingvarious embodiments of a method for transcoding data packets inaccordance with one embodiment of the present claimed invention.

FIG. 19 is a flowchart of the steps in a process for transcoding datapackets in accordance with one embodiment of the present claimedinvention.

FIG. 20 is a schematic representation of a data packet including headerdata and scalably encoded, progressively encrypted data in accordancewith one embodiment of the present claimed invention.

FIG. 21 is a schematic representation of a data packet includingscalably encoded, progressively encrypted data in accordance with oneembodiment of the present claimed invention.

The drawings referred to in this description should be understood as notbeing drawn to scale except if specifically noted.

BEST MODES FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with thepreferred embodiments, it will be understood that they are not intendedto limit the invention to these embodiments. On the contrary, theinvention is intended to cover alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it will be obvious toone of ordinary skill in the art that the present invention may bepracticed without these specific details. In other instances, well knownmethods, procedures, components, and circuits have not been described indetail as not to unnecessarily obscure aspects of the present invention.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the followingdiscussions, it is appreciated that throughout the present invention,discussions utilizing terms such as “receiving”, “segmenting”, “scalablyencoding”, “progressively encrypting” or the like, refer to the actionsand processes of a computer system, or similar electronic computingdevice. The computer system or similar electronic computing devicemanipulates and transforms data represented as physical (electronic)quantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission, or display devices. The present invention is also wellsuited to the use of other computer systems such as, for example,optical and mechanical computers.

Computer System Environment of the Present Secure Scalable StreamingInvention

With reference now to FIG. 5, portions of the present interrupt eventschaining method and system are comprised of computer-readable andcomputer-executable instructions which reside, for example, incomputer-usable media of a computer system. FIG. 5 illustrates anexemplary computer system 500 used in accordance with one embodiment ofthe present secure scalable streaming invention. It is appreciated thatsystem 500 of FIG. 5 is exemplary only and that the present inventioncan operate on or within a number of different computer systemsincluding general purpose networked computer systems, embedded computersystems, routers, switches, server devices, client devices, variousintermediate devices/nodes, stand alone computer systems, and the like.Additionally, computer system 500 of FIG. 5 is well adapted havingcomputer readable media such as, for example, a floppy disk, a compactdisc, and the like coupled thereto. Such computer readable media is notshown coupled to computer system 500 in FIG. 5 for purposes of clarity.

System 500 of FIG. 5 includes an address/data bus 502 for communicatinginformation, and a central processor unit 504 coupled to bus 502 forprocessing information and instructions. Central processor unit 504 maybe an 80×86-family microprocessor. System 500 also incudes data storagefeatures such as a computer usable volatile memory 506, e.g. randomaccess memory (RAM), coupled to bus 502 for storing information andinstructions for central processor unit 504, computer usablenon-volatile memory 508, e.g. read only memory (ROM), coupled to bus 502for storing static information and instructions for the centralprocessor unit 504, and a data storage unit 510 (e.g., a magnetic oroptical disk and disk drive) coupled to bus 502 for storing informationand instructions. System 500 of the present invention also includes anoptional alphanumeric input device 512 including alphanumeric andfunction keys coupled to bus 502 for communicating information andcommand selections to central processor unit 504. System 500 alsooptionally includes an optional cursor control device 514 coupled to bus502 for communicating user input information and command selections tocentral processor unit 504. System 500 of the present embodiment alsoincludes an optional display device 516 coupled to bus 502 fordisplaying information.

Referring still to FIG. 5, optional display device 516 of FIG. 5, may bea liquid crystal device, cathode ray tube, or other display devicesuitable for creating graphic images and alphanumeric charactersrecognizable to a user. Optional cursor control device 514 allows thecomputer user to dynamically signal the two dimensional movement of avisible symbol (cursor) on a display screen of display device 516. Manyimplementations of cursor control device 514 are known in the artincluding a trackball, mouse, touch pad, joystick or special keys onalphanumeric input device 512 capable of signaling movement of a givendirection or manner of displacement. Alternatively, it will beappreciated that a cursor can be directed and/or activated via inputfrom alphanumeric input device 512 using special keys and key sequencecommands. The present invention is also well suited to directing acursor by other means such as, for example, voice commands. A moredetailed discussion of the present secure scalable streaming inventionis found below.

General Description of the Present Secure Scalable Streaming Invention

With reference next to FIG. 6, FIG. 11, and FIG. 19, flow charts 600,1100, and 1900, respectively, illustrate exemplary steps used by thevarious embodiments of present invention. Flow charts 600, 1100, and1900 includes processes of the present invention which, in oneembodiment, are carried out by a processor under the control ofcomputer-readable and computer-executable instructions. Thecomputer-readable and computer-executable instructions reside, forexample, in data storage features such as computer usable volatilememory 506, computer usable non-volatile memory 508, and/or data storagedevice 510 of FIG. 5. The computer-readable and computer-executableinstructions are used to control or operate in conjunction with, forexample, central processing unit 504 of FIG. 5.

As an overview, the present invention is directed towards any data whichcan be scalably encoded and, specifically, any data that combinesscalable encoding with progressive encryption. For purposes of thepresent Application, scalable coding is defined as a process which takesoriginal data as input and creates scalably coded data as output, wherethe scalably coded data has the property that portions of it can be usedto reconstruct the original data with various quality levels.Specifically, the scalably coded data is often thought of as an embeddedbitstream. The first portion of the bitstream can be used to decode abaseline-quality reconstruction of the original data, without requiringany information from the remainder of the bitstream, and progressivelylarger portions of the bitstream can be used to decode improvedreconstructions of the original data. For purposes of the presentApplication, progressive encryption is defined as a process which takesoriginal data (plaintext) as input and creates progressively encrypteddata (ciphertext) as output, where the progressively encrypted data hasthe property that the first portion can be decrypted alone, withoutrequiring information from the remainder of the original data; andprogressively larger portions can be decrypted with this same property,in which decryption can require data from earlier but not later portionsof the bitstream.

Encoding Method and System

Although specific steps are disclosed in flow chart 600 of FIG. 6, suchsteps are exemplary. That is, the present invention is well suited toperforming various other steps or variations of the steps recited inFIG. 6. Additionally, for purposes of clarity and brevity, the followingdiscussion and examples will specifically deal with video data. Thepresent invention, however, is not limited solely to use with videodata. Instead, the present invention is well suited to use withaudio-based data, image-based data, web page-based data, graphic dataand the like. Specifically, the present invention is directed towardsany data in which scalable coding is combined with progressiveencryption. In step 602 of FIG. 6, in one embodiment, the presentinvention recites receiving video data. In one embodiment, the videodata is comprised of a stream of uncompressed video frames which arereceived by segmenter 702 of the encoder system 700 of FIG. 7.

In another embodiment of the present invention, the video data iscomprised of prediction error video data generated by a video predictionunit (VPU). As shown FIG. 8, in one embodiment of the present inventionencoder system 700 has a VPU 800 coupled thereto. VPU 800 generates andforwards prediction error video data to segmenter 702 of encoder system700. Although VPU 800 of FIG. 8 is disposed outside of encoding system700, the present invention is also well suited to having VPU 800integral with encoding system 700. FIG. 9 illustrates one embodiment ofthe present invention in which VPU 800 is integral with encoding system700.

With reference now to step 604 of FIG. 6, the present embodiment thensegments the received video data into corresponding regions. FIG. 10Aprovides a schematic depiction of a video frame 1000. Video datacorresponding to video frame 1000 is received by segmenter 702 of FIGS.7, 8, and 9. FIG. 10B depicts the same video frame 1000 after segmenter702 has segmented video frame 1000 into corresponding regions 1002,1004, 1006, 1008, 1010, and 1012. Although such a quantity andconfiguration of regions is shown in FIG. 10B, such a tiling quantityand configuration is intended to be exemplary only. As one example, FIG.10C illustrates another example of segmentation in which segmenter 702has segmented video frame 100 into various non-rectangular regions 1014,1016, 1018, 1020, and 1022. As another example, FIG. 10D illustratesanother example of segmentation in which segmenter 702 has segmentedvideo frame 100 into various non-rectangular and overlapping regions1024, 1026, 1028, 1030, and 1032. The overlapping portions are denotedby dofted lines. The present invention is also well suited to anapproach in which segmenter 702 has various rectangular regionsconfigured in an overlapping arrangement. Furthermore, the presentinvention is also well suited to an embodiment in which the regionschange from frame to frame. Such an embodiment is employed, for example,to track a foreground person as they move.

Referring now to step 606, encoder 704 of FIGS. 7, 8 and 9 then scalablyencodes the regions into scalable video data. For purposes of thepresent Application, scalable coding is defined as a process which takesoriginal data as input and creates scalably coded data as output, wherethe scalably coded data has the property that portions of it can be usedto reconstruct the original data with various quality levels.Specifically, the scalably coded data is often thought of as an embeddedbitstream. The first portion of the bitstream can be used to decode abaseline-quality reconstruction of the original data, without requiringany information from the remainder of the bitstream, and progressivelylarger portions of the bitstream can be used to decode improvedreconstructions of the original data. That is, separate regions orregions of a video frame are encoded into one or more data packets. Thescalable video data generated by the present embodiment has the propertythat a first small portion of the data can be decoded into baselinequality video, and larger portions can be decoded into improved qualityvideo. It is this property that allows data packets to be transcoded tolower bitrates or spatial resolutions simply by truncating the datapacket. This process of truncation will be discussed in further detailbelow.

With reference still to step 606, in one embodiment of the presentinvention each region is coded by encoder 704 into two portions: headerdata and scalable video data. Hence, in such an embodiment, each datapacket contains header data and scalable video data. The header datadescribes, for example, the region (e.g. the location of the regionwithin the video frame) that the data packet represents and otherinformation used for subsequent transcoding and decoding operations inaccordance with the present invention. Furthermore, in one embodiment,the header data contains information including a series of recommendedtruncation points for data packet transcoders. The scalable video datacontains the actual coded video. In the case of intraframe coding, thevideo data may be the coded pixels; while in the case of interframecoding, it may be the motion vectors and coded residuals that resultfrom motion-compensated prediction. In the present embodiments, scalablecoding techniques are used in both cases to create an embedded orscalable data packet that can be truncated to lower the resolution orfidelity of the coded video data. In still another embodiment of thepresent invention, the scalably encoded video data is prepared byencoder 704 without corresponding header data.

As recited in step 608, the present embodiment then progressivelyencrypts the scalable video data to generate progressively encryptedscalable video data. That is, packetizer and encrypter 706 of FIGS. 7,8, and 9 employs progressive encryption techniques to encrypt thescalable video data. For purposes of the present Application,progressive encryption is defined as a process which takes original data(plaintext) as input and creates progressively encrypted data(ciphertext) as output, where the progressively encrypted data has theproperty that the first portion can be decrypted alone, withoutrequiring information from the remainder of the original data; andprogressively larger portions can be decrypted with this same property,in which decryption can require data from earlier but not later portionsof the bitstream. Progressive encryption techniques include, forexample, cipher block chains or stream ciphers. These progressiveencryption methods have the property that the first portion of the datais encrypted independently, then later portions are encrypted based onearlier portions. When properly matched with scalable coding andpacketization, progressive encryption preserves the ability to transcodedata packets with simple data packet truncation. More specifically,progressive encryption methods have the property that smaller blocks ofdata are encrypted progressively. While block code encryption with smallblock sizes is not very secure, progressive encryption methods add adegree of security by feeding encrypted data of earlier blocks into theencryption of a later block. Decryption can then be performedprogressively as well. In one embodiment, the first small block ofciphertext is decrypted into plaintext by itself while later blocks ofciphertext depend on the decrypted plaintext from earlier blocks. Thus,earlier blocks of ciphertext can be decrypted without knowledge of theentire ciphertext segment. This progressive nature of cipher blockchains and stream ciphers matches nicely with the progressive orembedded nature of scalable coding. Although encoding system 700 depictsa combined packetizer and encrypter module 706. Such a depiction isexemplary only, as encoding system 700 of the present invention is wellsuited to having separate and distinct packetizer and encrypter modules.

As was the case in prior art approaches, entire data packets wereencrypted with one long block code. As a result, decryption was notpossible unless it the data packet was received in its entirety.However, the present invention is using scalable data packets and it isdesired to transcode the stream of scalable data packets by data packettruncation. Therefore, the present invention encrypts the data packetsin a similarly progressive manner. Hence, unlike conventionalapproaches, the present invention is data packet loss resilient. Thatis, should a data packet be lost, decryption of the remaining datapackets is not further complicated and is still readily achievable. Thiscombination of scalable encoding and progressive encryption enables theadvantageous transcoding operations described in detail below.

With reference still to step 608, in one embodiment of the presentinvention, while the payload data (i.e. the scalable video data) isencrypted progressively, the header data is left unencrypted so thattranscoding nodes can use this information to make transcodingdecisions. For example, in one embodiment, the unencrypted headercontains information such as recommended truncation points within theencrypted payload data. In another embodiment, this header data is usedto achieve near rate distortion (RD)-optimal bitrate reduction byintermediate transcoding nodes. Moreover, in the present embodiment, thetranscoding nodes can use the header data to make transcoding decisionswithout requiring decryption of the progressively encrypted scalablevideo data or the header data. In yet another embodiment of the presentinvention the header data is encrypted to add additional security.

Referring now to step 610, the present invention then packetizes theprogressively encrypted scalable video data. In one embodiment, apacketizer and encrypter 706 of FIGS. 7, 8, and 9 combine and packetizethe unencrypted header data with the progressively encrypted scalablevideo data. The resulting secure scalable data packets are thenavailable to be streamed to desired receivers. In another embodiment,packetizer and encrypter 706 packetizes the progressively encryptedscalable video data and the encrypted header data. Furthermore, in anembodiment which does not include header data, packetizer and encrypter706 packetizes only the progressively encrypted scalable video data.

Encoding system 700 securely and scalably encodes video data. Morespecifically, encoding system 700 combines scalable coding withprogressive encryption techniques. The resulting scalably encoded,progressively encrypted, and packetized video streams have the featurethat subsequent transcoding operations such as bitrate reduction andspatial downsampling can be performed (via e.g. data packet truncationor data packet elimination) without decrypting the packetized data andthus while maintaining the security of the system. The present inventionis also well suited to an embodiment in which only some, but not all, ofthe regions formed by segmenter 702 are ultimately forwarded fromencoding system 700. As an example, in one embodiment of the foregroundof a video data image is forwarded, as the background image may not havechanged since a previous transmission, or perhaps the background imagedoes not contain data of interest.

Decoding Method and System

Although specific steps are disclosed in flow chart 1100 of FIG. 11,such steps are exemplary. That is, the present invention is well suitedto performing various other steps or variations of the steps recited inFIG. 11. In step 1102 of FIG. 11, the present invention receives a datapacket containing progressively encrypted and scalably encoded videodata. More specifically, decrypter 1202 of decoding system 1200, both ofFIG. 12, receives the data packet containing progressively encrypted andscalably encoded video data. In one embodiment, the received data packetalso includes header data wherein the header data provides informationcorresponding to the scalably encoded video data. In yet anotherembodiment, the received data packet also includes encrypted header dataproviding information corresponding to the scalably encoded video data.

As recited in step 1104, the present invention then decrypts the datapacket containing the progressively encrypted and scalably encoded videodata to generate scalably encoded regions. That is, decrypter 1202 ofFIG. 12 decrypts the progressively encrypted and scalably encoded videodata to generate scalably encoded regions. Furthermore, in an embodimentin which the received data packet includes encrypted header data,decrypter 1202 also decrypts the encrypted header data.

Referring now to step 1106, the present embodiment then decodes thescalably encoded regions to provide decoded regions. As described abovein conjunction with the description of encoding system 700 of FIGS. 7,8, and 9, a video frame 1000 as shown in FIG. 10A can be segmented inmultiple corresponding regions 1002, 1004, 1006, 1008, 1010, and 1012 asshown in FIG. 10B.

At step 1108, the present invention then assembles the decoded regionsto provide video data. Moreover, assembler 1206 of decoding system 1200of FIG. 12 assembles the decoded regions to provide video data. In oneembodiment of the present invention decoding system 1200 then providesas output, video data in the form of an uncompressed video stream. Inanother embodiment of the present invention, assembler 1206 outputsvideo data comprised of prediction error video data suitable for by avideo prediction unit (VPU). As shown FIG. 13, in one embodiment of thepresent invention decoder system 1200 has a VPU 1300 coupled thereto.VPU 1300 uses the output of assembler 1206 to ultimately provide anuncompressed stream of video frame data. Although VPU 1300 of FIG. 13 isdisposed outside of decoding system 1200, the present invention is alsowell suited to having VPU 1300 integral with decoding system 1200. FIG.14 illustrates one embodiment of the present invention in which VPU 1300is integral with decoding system 1200. Hence, the present inventionprovides a method and system for decoding video data which has beensecurely and scalably encoded.

Transcoding Method and System

FIG. 15A is a block diagram of an exemplary hybrid wired/wirelessnetwork 1500 upon which embodiments of the present invention may bepracticed. In hybrid wired/wireless network 1500, media (e.g., video)data are streamed to fixed clients (stationary receiving nodes) via awired link and to mobile clients (moving receiving nodes) via a wirelesslink.

In the present embodiment, hybrid wired/wireless network 1500 includes awired sender (source 1510), a wired high-resolution receiver 1520, and awireless medium-resolution receiver 1540. In this system, source 1510generates a full-bandwidth, high-resolution video stream 1550 a that issent to high-resolution receiver 1520. A transcoder 1530, placed atsource 1510, at medium-resolution receiver 1540, or at an intermediatenode such as a wired/wireless gateway, transcodes the stream 1550 a intoa lower-bandwidth, medium-resolution video stream 1550 b which is thensent to medium-resolution receiver 1540.

FIG. 15B is a block diagram of an exemplary wireless network 1501 (e.g.,a wireless appliance network) upon which embodiments of the presentinvention may be practiced. In wireless appliance networks, mobilesenders and receivers communicate with one another over wireless links.A sender's coverage area is limited by the power of the transmittedsignal. Relay devices can be used to extend the wireless coverage areawhen intended receivers are beyond the immediate coverage area of thesender. In the case of heterogeneous receivers (e.g., receiving nodeshaving different display, power, computational, and communicationcharacteristics and capabilities), transcoders can be used to adapt avideo stream for a particular receiver or communication link.Transcoding can be performed in a relay device or in a receiver whichalso acts as a relay. Transcoding can also be performed by the sender orby the receiving node.

In the present embodiment, wireless network 1501 includes a wirelesssender (source 1510), a high-resolution receiver and transcoder 1560,and a medium-resolution (lower bandwidth) receiver 1540. In wirelessnetwork 1501, the high-resolution receiver 1560 receives and transcodesthe high-resolution video stream 1550 a, and relays the resultinglower-bandwidth stream 1550 b to the medium-resolution receiver 1540.

Referring to FIGS. 15A and 15B, both hybrid wired/wireless network 1500and wireless network 1501 use network transcoders to transcode videostreams 1550 a into lower bandwidth streams 1550 b that match thedisplay capabilities of the target wireless nodes (e.g.,medium-resolution receiver 1540). Generally speaking, these networksillustrate how network transcoding can enable efficient use of wirelessspectrum and receiver resources by transcoding media (e.g., video)streams into formats better suited for transmission over particularchannels and for the capabilities of the receiving nodes.

FIG. 16 is a block diagram of a system 1600 including a source node1610, an intermediate (transcoder) node 1620, and a receiving node 1630in accordance with one embodiment of the present invention. In thisembodiment, transcoder 1620 is a separate node transposed between sourcenode 1610 and receiving node 1630. However, the functions performed bytranscoder 1620 may instead be performed by source node 1610 or byreceiving node 1630.

In the present embodiment, source node 1610 encodes and/or encrypts astream of data packets and sends these data packets to transcoder 1620,as described above. In one embodiment, each of the data packets in thestream has a header portion and a payload portion (see FIG. 20, below);in another embodiment, the data packet has only a payload portion (seeFIG. 21, below). The payload portion carries the media data (e.g., videodata), while the header portion carries information that is used bytranscoder 1620 to transcode the payload portion. A data packet,including the information carried by the header portion, and thetranscoding method used by transcoder 1620 are further described below.In one embodiment, only the payload portion is encrypted and encoded. Inanother embodiment, the payload portion is encrypted and encoded, andthe header portion is also encrypted.

In the present embodiment, transcoder 1620 performs a transcodingfunction on the data packets received from source node 1610. Thetranscoding function performed by transcoder 1620 is described inconjunction with FIG. 19, below. The purpose of the transcoding functionis to configure the stream of data packets according to the attributesdownstream of transcoder 1620, such as the attributes of the receivingnode 1630 or the attributes of communication channel 1625 linkingtranscoder 1620 and receiving node 1630. The transcoding function caninclude, for example, truncation of the data packets or elimination ofcertain data packets from the stream. In the case in which the stream isalready configured for the receiving node 1630 or for communicationchannel 1625, the transcoding function consists of a pass-through of thedata packets in the stream without modification.

Of particular significance, in accordance with the present invention,transcoder 1620 performs a transcoding function without decryptingand/or decoding the data packets (specifically, the media data in thedata packets). In the embodiment in which the data packets have a headerportion and a payload portion, and where the header portion isencrypted, transcoder 1620 only decrypts the header portion. In eithercase, in comparison to a conventional transcoder, transcoder 1620 of thepresent invention requires less computational resources because there isno need to decrypt the media data. In addition, the present inventionprovides end-to-end security while enabling very low complexitytranscoding to be performed at intermediate, possibly untrusted, nodeswithout compromising the security of the media data.

Continuing with reference to FIG. 16, transcoder 1620 has knowledge ofthe attributes of receiving node 1630 and/or communication channel 1625.These attributes include, but are not limited to, the display, power,communication and computational capabilities and characteristics ofreceiving node 1630, or the available bandwidth on communication channel1625. For example, in one embodiment, transcoder 1620 receives theattribute information from receiving node 1630, or transcoder 1620 readsthis information from receiving node 1630. In another embodiment,transcoder 1620 may be implemented as a router in a network; the routercan determine if there is congestion on the next “hop” and transcode thestream of data packets accordingly.

In the present embodiment, after transcoding, transcoder 1620 sends theresultant stream of data packets, comprising the encoded and encryptedmedia data packets, to receiving node 1630.

FIG. 17 is a block diagram of one embodiment of a transcoder device 1620upon which embodiments of the present invention may be practiced. Inthis embodiment, transcoder 1620 includes a receiver 1710 and atransmitter 1720 for receiving a stream of data packets from source node1610 (FIG. 16) and for sending a stream of data packets to receivingnode 1630 (FIG. 16), respectively. Receiver 1710 and transmitter 1720are capable of either wired or wireless communication. Separatereceivers and transmitters, one for wired communication and one forwireless communication, may also be used. It is appreciated thatreceiver 1710 and transmitter 1720 may be integrated as a single device(e.g., a transceiver).

Continuing with reference to FIG. 17, transcoder device 1620 may includean optional controller 1730 (e.g., a processor or microprocessor), anoptional decrypter 1740, and an optional memory 1750, or a combinationthereof. In one embodiment, decrypter 1740 is used to decrypt headerinformation. In another embodiment, memory 1750 is used to accumulatedata packets received from source node 1610 before they are forwarded toreceiving node 1630 (FIG. 16).

FIGS. 18A, 18B, 18C, 18D and 18E are data flow diagrams illustratingvarious embodiments of a method for transcoding data packets inaccordance with the present invention. In the embodiments of FIGS.18A-D, the data packets each have a header portion and a payloadportion; in the embodiment of FIG. 18E, the data packets do not have aheader portion. In each of the embodiments of FIGS. 18A-E, the datapackets (specifically, the media data) are encrypted and may be encoded.The embodiments of FIGS. 18A-E are separately described in order to moreclearly describe certain aspects of the present invention; however, itis appreciated that the present invention may be implemented bycombining elements of these embodiments.

In accordance with the present invention, the method for transcodingdata packets is performed on the encrypted data packets; that is, themedia data are not decrypted. Transcoding functions can includetruncation of the data packets (specifically, the payload portions ofthe data packets), eliminating certain data packets from the stream, orpassing the data packets through without modification.

With reference first to FIG. 18A, incoming encrypted and/or encoded datapackets are received by transcoder 1620. In this embodiment, the headerportion of each data packet is not encrypted. Transcoder 1620 reads theheader portion, which contains information that can be used to maketranscoding decisions. In one embodiment, the information in the headerportion includes specification of the truncation points. In anotherembodiment, the truncation points are derived from the informationprovided in the header.

For example, the header portion may contain information specifyingrecommended points (e.g., a number of a bit) for truncating the payloadportion of the data packets. It is appreciated that each data packet mayhave a different truncation point. The recommended truncation point canbe selected using a variety of techniques. In one embodiment, thetruncation point for each data packet is specified according to ananalysis such as a rate-distortion (RD) analysis, so that the stream ofdata packets can be compressed to a rate that is RD optimal or near-RDoptimal. In another embodiment, the header portion contains informationthat describes the RD curves generated by the RD analysis, and thetruncation points are derived from further analysis of the RD curves.

In the present embodiment, RD optimal coding is achieved by generatingan RD plot for each region of a video image, and then operating on allregions at the same slope that generates the desired total bitrate.Near-optimal transcoding can be achieved at the data packet level byplacing the optimal RD cutoff points for a number of quality levels inthe header portions of the data packets. Then, transcoder 1620 (FIG. 16)can truncate each packet at the appropriate cutoff point; thus, theresulting packets will contain the appropriate number of bits for eachregion of the image for the desired quality level. Transcoder 1620 readseach packet header, then truncates the packet at the appropriate point.For example, if three regions in an image are coded into separatepackets, for each region three RD optimal truncation points areidentified and their locations placed in the respective packet header.Transcoder 1620 can choose to operate at any of the three RD points (orpoints in between), and then can truncate each packet at the appropriatecutoff point.

The header portion may also contain information identifying each datapacket by number, for example. Accordingly, transcoder 1620 caneliminate certain data packets from the stream; for example, if everyother packet is to be eliminated (e.g., the odd-numbered packets),transcoder 1620 can use the header information to identify theodd-numbered data packets and eliminate those from the stream of datapackets.

The embodiment of FIG. 18B is similar to that of FIG. 18A, except thatthe header portion of each data packet is encrypted. In this case,transcoder 1620 first decrypts the header portion, before reading theheader information and operating on the stream of data packets asdescribed above.

In the embodiment of FIG. 18C, data packets are accumulated in memory.That is, instead of a first-in/first-out type of approach, a subset ofthe data packets in the stream is accumulated and stored in memory(e.g., memory 1750 of FIG. 17) before they are forwarded to thereceiving node. In this embodiment, the header information for all ofthe accumulated data packets in the subset is used to make transcodingdecisions. The transcoding decisions are made based on the attributes ofthe receiving node 1630 or the attributes of the communication channel1625 (FIG. 16), as described previously herein. It may be possible, andperhaps desirable, to configure the stream of data packets according tothe attributes of the receiving node or communication channel withoutoperating on every data packet in the stream. For example, instead oftruncating all of the data packets in the subset, a decision may be madeto truncate only a portion of the packets in the subset, or to truncatethe packets at a point other than the recommended truncation point.

In the embodiment of FIG. 18D, transcoder 1620 receives information fromthe downstream receiving node (e.g., receiving node 1630 of FIG. 16). Inone embodiment, the information describes attributes of receiving node1630, such as its display, power, computational and communicationcapabilities and characteristics. Based on the information received fromreceiving node 1630, transcoder 1620 can make transcoding decisionsbased on the information in the header portions of the data packets. Forexample, transcoder 1620 can pick a truncation point depending onwhether receiving node 1630 is a medium- or low-resolution device, andtranscoder 1620 can choose not to modify the stream of data packets ifreceiving node 1630 is a high-resolution device. Similarly, transcoder1620 can receive information describing the attributes of communicationchannel 1625 (FIG. 16)

In the embodiment of FIG. 18E, the incoming data packets do not have aheader portion. Accordingly, transcoder 1620 makes transcoding decisionsbased on a pre-defined set of rules. That is, instead of truncating eachdata packet at a different point specified by the information in theheader portion, transcoder 1620 may truncate all data packets in thestream at the same point, depending on the attributes of the receivingnode or communication channel.

FIG. 19 is a flowchart of the steps in a process 1900 for transcodingdata packets in accordance with one embodiment of the present invention.In one embodiment, process 1900 is implemented by transcoder device 1620(FIG. 17) as computer-readable program instructions stored in memory1750 and executed by controller 1730. Although specific steps aredisclosed in of FIG. 19, such steps are exemplary. That is, the presentinvention is well suited to performing various other steps or variationsof the steps recited in FIG. 19.

In step 1910 of FIG. 19, a stream of data packets is received from asource node (e.g., source 1610 of FIG. 16). In the present embodiment,the data packets include encrypted media data (e.g., video data). In oneembodiment, the media data are also encoded. In another embodiment, thedata packets include a header portion and a payload portion. In oneembodiment, the header portion is also encrypted.

In step 1915 of FIG. 19, in one embodiment, information describing theattributes of a downstream receiving node (e.g., receiving node 1630 ofFIG. 16) or communication channel (e.g., communication channel 1625 ofFIG. 16) is received. In another embodiment, the attributes of receivingnode 1630 or communication channel 1625 are already known.

In step 1920 of FIG. 19, a transcoding function is performed on thestream of data packets to configure the stream according to theattributes of receiving node 1630. Significantly, the transcodingfunction is performed without decrypting the media data in the datapackets. In one embodiment, the transcoding function is performed oninformation provided by the header portion of each data packet. In onesuch embodiment, the header information provides recommended truncationpoints for the payload portion of the respective data packet. In anotherembodiment, the truncation points are derived from the informationprovided in the header portion.

In step 1922, in one embodiment, the transcoding function eliminatescertain data packets from the stream. In step 1924, in one embodiment,the transcoding function truncates the media data in the data packets.It is appreciated that each data packet may have a different truncationpoint. In step 1926, in one embodiment, the transcoding function passesthe data packets through without modification.

In step 1930, the transcoded data packets (still encrypted and/orencoded) are sent to receiving node 1630.

In summary, the above-listed embodiment of the present inventionprovides a secure method and system for transcoding media data for avariety of downstream attributes, such as the attributes of receivingnodes having different capabilities and characteristics or theattributes of the communication between the transcoder and a receivingnode. Because the encrypted media data do not need to be decrypted andthen encrypted again, the computational resources needed for transcodingthe stream of data packets is significantly reduced, and the security ofthe media data is not compromised.

Secure Scalable Data Packet

With reference now to FIG. 20, a schematic representation of a datapacket 2000 formed in accordance with one embodiment of the presentinvention is shown. Furthermore, as mentioned above, for purposes ofclarity and brevity, the following discussion and examples willspecifically deal with video data. The present invention, however, isnot limited solely to use with video data. Instead, the presentinvention is well suited to use with audio-based data, image-based data,web page-based data, and the like. It will be understood that in thepresent embodiments, data packet 2000 is generated by encoding system700 of FIGS. 7, 8, and 9, operated on by transcoder 1620 of FIGS. 16,18A, 18B, 18C, 18D, and 18E, and then ultimately forwarded to decodingsystem 1200 of FIGS. 12, 13, and 14. During the aforementioned process,data packet 2000 is stored on computer readable media residing in, andcauses a functional change or directs the operation of, the devices(e.g. general purpose networked computer systems, embedded computersystems, routers, switches, server devices, client devices, variousintermediate devices/nodes, stand alone computer systems, and the like)in which, for example, transcoder 1620 and/or decoder 1200 areimplemented.

In the embodiment of FIG. 20, data packet 2000 includes header dataportion 2002 and scalably encoded, progressively encrypted video dataportion 2004. As mentioned above, header data portion 2002 includesinformation that is used by transcoder 1620 to transcode the scalablyencoded, progressively encrypted video data portion 2004. For example,header data portion 2002 may contain information specifying recommendedpoints (e.g., a number of a bit) for truncating the payload portion(i.e. the scalably encoded, progressively encrypted video data portion2004) of data packet 2000. Header data portion 2002 may also containinformation identifying each data packet by number, for example.Accordingly, transcoder 1620 can eliminate certain data packets from thestream; for example, if every other packet is to be eliminated (e.g.,the odd-numbered packets), transcoder 1620 can use the information inheader data portion 2002 to identify the odd-numbered data packets andeliminate those from the stream of data packets.

With reference still to FIG. 20, data packet 2000 also includespotential truncation points 2006, 2008, and 2010 within scalablyencoded, progressively encrypted video data portion 2004. Although suchtruncation points are shown in FIG. 20, the configuration of truncationpoints 2006, 2008, and 2010, is exemplary only. That is, the presentinvention is well suited to having a lesser of greater number oftruncation points, and to having the truncation points located otherthan where shown in FIG. 20. Again, as mentioned above, truncationpoints 2006, 2008, and 2010 are used by transcoder 1620 during itsoperation on packet 2000. Additionally, in one embodiment of the presentinvention, header data portion 2002 is encrypted.

In the embodiment of FIG. 21, data packet 2100 does not include a headerdata portion, and instead includes only scalably encoded, progressivelyencrypted video data portion 2104. With reference still to FIG. 21, datapacket 2100 also includes potential truncation points 2104, 2106, and2108 within scalably encoded, progressively encrypted video data portion2104. Although such truncation points are shown in FIG. 21, theconfiguration of truncation points 2104, 2106, and 2108, is exemplaryonly. That is, the present invention is well suited to having a lesserof greater number of truncation points, and to having the truncationpoints located other than where shown in FIG. 21. Again, as mentionedabove, truncation points 2104, 2106, and 2108 are used by transcoder1620 during its operation on packet 2100.

Thus, the present invention provides, in one embodiment, a secure andscalable encoding method and system for use in the streaming of data.The present invention further provides, in one embodiment, a method fordecoding data which has been securely and scalably encoded.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the Claims appended hereto and theirequivalents.

1-49. (canceled)
 50. A method for decoding data which has been securelyand scalably encoded, said method comprising: accessing progressivelyencrypted and scalably encoded data, wherein any portion of saidprogressively encrypted and scalably encoded data is decryptable in asingle decryption operation; decrypting said progressively encrypted andscalably encoded data to produce scalably encoded data; and decodingsaid scalably encoded data to produce decoded data.
 51. The method ofclaim 50 further comprising assembling said decoded data to providevideo frame data.
 52. The method of claim 50 further comprisingassembling said decoded data to provide prediction error video data. 53.The method of claim 50 wherein said progressively encrypted and scalablyencoded data is packetized.
 54. The method of claim 50 wherein saidprogressively encrypted and scalably encoded data comprises header datathat provides information corresponding to said scalably encoded data.55. The method of claim 50 wherein said progressively encrypted andscalably encoded data comprises data selected from the group consistingof: video data, audio data, image data, graphic data, and web page data.56. A method for securely and scalably encoding data, said methodcomprising: scalably encoding data into scalable data; and progressivelyencrypting said scalable data to generate progressively encryptedscalable data, wherein said progressively encrypted scalable data istranscodable while said progressively encrypted scalable data remainsencrypted.
 57. The method of claim 56 further comprising generatingheader data that provides information corresponding to said scalabledata.
 58. The method of claim 57 further comprising encrypting saidheader data to provide encrypted header data.
 59. The method of claim 57further comprising packetizing said progressively encrypted scalabledata and said header data.
 60. The method of claim 56 further comprisingpacketizing said progressively encrypted scalable data.
 61. The methodof claim 56 wherein said data is selected from the group consisting of:video data, audio data, image data, graphic data, and web page data. 62.The method of claim 56 further comprising segmenting said data intocorresponding regions.
 63. A method for securely and scalably encodingdata, said method comprising: scalably encoding data into scalable datacomprising a plurality of blocks of data; progressively encrypting saidscalable data to generate progressively encrypted scalable data, whereinany portion of said progressively encrypted scalable data is decryptablein a single decryption operation; and packetizing said progressivelyencrypted scalable data.
 64. The method of claim 63 further comprisinggenerating header data that provides information corresponding to saidscalable data.
 65. The method of claim 64 further comprising encryptingsaid header data to provide encrypted header data.
 66. The method ofclaim 65 wherein said step packetizing further comprises packetizingsaid progressively encrypted scalable data and said encrypted headerdata.
 67. The method of claim 64 wherein said packetizing furthercomprises packetizing said progressively encrypted scalable data andsaid header data.
 68. The method of claim 63 wherein said data isselected from the group consisting of: video data, audio data, imagedata, graphic data, and web page data.
 69. The method of claim 63further comprising segmenting said data into corresponding regions.